MTSM/mods/plantlife_modpack/cavestuff/mapgen.lua

--Map Generation Stuff

minetest.register_on_generated(function(minp, maxp, seed)
	if maxp.y >= 2 and minp.y <= 0 then
		-- Generate pebbles
		local perlin1 = minetest.get_perlin(329, 3, 0.6, 100)
		-- Assume X and Z lengths are equal
		local divlen = 16
		local divs = (maxp.x-minp.x)/divlen+1;
		for divx=0,divs-1 do
		for divz=0,divs-1 do
			local x0 = minp.x + math.floor((divx+0)*divlen)
			local z0 = minp.z + math.floor((divz+0)*divlen)
			local x1 = minp.x + math.floor((divx+1)*divlen)
			local z1 = minp.z + math.floor((divz+1)*divlen)
			-- Determine pebble amount from perlin noise
			local pebble_amount = math.floor(perlin1:get2d({x=x0, y=z0}) ^ 2 * 2)
			-- Find random positions for pebbles based on this random
			local pr = PseudoRandom(seed+1)
			for i=0,pebble_amount do
				local x = pr:next(x0, x1)
				local z = pr:next(z0, z1)
				-- Find ground level (0...15)
				local ground_y = nil
				for y=30,0,-1 do
					if minetest.get_node({x=x,y=y,z=z}).name ~= "air" then
						ground_y = y
						break
					end
				end

				if ground_y then
					local p = {x=x,y=ground_y+1,z=z}
					local nn = minetest.get_node(p).name
					-- Check if the node can be replaced
					if minetest.registered_nodes[nn] and
						minetest.registered_nodes[nn].buildable_to then
						nn = minetest.get_node({x=x,y=ground_y,z=z}).name
						-- If desert sand, add dry shrub
						if nn == "default:dirt_with_grass" then
							minetest.swap_node(p,{name="cavestuff:pebble_"..pr:next(1,2), param2=math.random(0,3)})
						elseif nn == "default:desert_sand" then
							minetest.swap_node(p,{name="cavestuff:desert_pebble_"..pr:next(1,2), param2=math.random(0,3)})
					    end
					end
				end

			end
		end
		end
	end
end)